Lightning-arrester



(No Model.) 2 Sheets-Sheet 1.

E. THOMSON. LIGHTNING ARRESTER.

No. 454,672. Patented June 28,1891.

Fi iaka-5% (No Model.) 2 Sheets-Sheet 2.

E. THOMSON. LIGHTNING ARRESTER.

No. 454,672. Patented June 23,1891.

UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

LlGHTNlNG-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 454,672, dated June 23, 1891. Application filed November 5,1890. Serial No, 370,364. (No model.)

To all whom it may concern:

Be it known that I, ELIHU Tnonsow, a citizen of the United States, residing at Lynn, in the county of Essex and State of Massaehusetts, have invented a certain new and useful Improvementin Lightning-Arresters,of which the following is a specification.

My present invention relates to lightningarresters, and in using this term my intention is to include discharge-proteetors of all 7 kinds for avoiding injury to the apparatus protected arising from lightning or other dis charges of dangerously high potential from the line.

The object which I have had immediately in View is to guard against the formation or maintenance of arcs across the dischargeplates of arresters of this character; and the apparatus I have devised for this purpose consists in its most approved form of a eounter-electro-motive-foree generator in the form of a number of polarizing-cells in series with the discharge-plates and divided into sections,eachsectionbeiugshunted bydischargeplates in series with one another and with the first-named plates.

For use with alternating currents the polarizing-cells would be replaced by counterinduetive devices, and in some cases in operating with direct currents the polarizingcells may be used without the shuntingplates.

Figures 1 to l are diagrams showing the application of the polarizing-cells in series with the discharge-plates, which formsone feature of my present invention. Fig. 5 shows the polai'izingcells. Figs. 6 and 7 are diagrams of the most approved form of the invention, as above described. Figs 8 and 9 show in a similar manner the use of counterinduct-ive devices in place of the polarizingcells, and Fig. 10 is a detail of the form of inductive device which may be employed.

L represents a line-circuit which it is desired to protect from lightning or other high potential discharges. It is therefore provided with a lightning-arrester comprising .ihe discharge plates or surfaces P P, separated by an insulating interval and connected, respectively, with the line and the earth-plate E. Vere no further provision made, a discharge in passing to ground would form an arc across the jumping-space between the plates P P, and some special form of are-interrupter would be needed for extinguishing the are. I avoid this arcing by using a series of polarizing-cells O, which may be interposed anywhere in the discharge-path, so that the whole or a portion of the discharge will pass through them and thereby generate a counter electro-motive force opposing the discharge.

In Fig. 1 the generator 0 is arranged between the arrester-plate P and earth-plate E, while in Fig. 2 it is situated between the line L and arrester-plate P. In Fig. I} it is divided into two portions-one between the line L and plate P and the other between the second plate P and ground. In Fig. I two sets of arrester-plates P P and P P" are arranged in series, and the generator is connected to the intermediate plates P and P In all these modifications, however, as well as in the others hereinafter described, the circuit through the generator is normally broken at the jumpingspace between the dischargeplates; but when the discharge leaps this space it polarizes the plates of the cells and at once generates a counter electro-motive force, which tends to exhaust the arcing potential. This, together with the resistance due to the jumping-space itself, will quickly cause the are to break.

The number of coils provided at C will be in excess of that required to set up an electro-motive force equal to the elcctro-motive force of the line, and thereby provide a margin of safety in guarding against the flow of current from the line to earth, although the number may of course be reduced to an extent such that the electroauotive force of the coils, together with that required to sustain an are at 1 1 when once formed, shall be greater than the clectro-niotive force upon the line.

Fig. 5 illustrates in detail the countercloctro-motive-force generating polarizing-cells, which I employ. It consists of successive metal plates Msueh, for instance, as lead plates-separated by a moist substance, which may be either a liquid itself or a strip of felt F soaked in one, such as a salt or acid, the whole constituting a series of cells, as I have termed them herein.

este /2 The principle of operation shown in Figs. 1 to i I prefer to employ in the more extended manner shown in Fig. (i, where successive sets or sections of polarizing-cells B B B &c.,

5 are placed in series with the discharge-plates P P, and each set or section is connected in shunt by connections a b c, the, with the discharge-plates P P P 870., which are arranged inseries withoneanotherandalsoinseries with no the discharge or jumping space between P P.

The counter electromotive force generated by each set or section of the polarizing-cells is made insufficient to sustain an are between the arrester-plates in shunt therewith, so that I 5 the discharge goes to earth either wholly or the same arrangement applied to both sides of a circuit, as a double-pole lightning-arrester.

In case alternating currents are employed counter-inductive devices 0 0' 0 &e., should be substituted for the polarizing-cells in the manner shown in Figs. 8 and 9, while still preserving some of the features and the general arrangement of Figs. 6 and '7. Such counter'inductive devices ma" consist of a 0 number of coils wound on a common core I,

which, as shown in Fig. 10, may be a closed iron ring. As before, the counter electro-motive force generated by each section is insufficient to maintain an are between the arrest- 3 5 er-plates.

that I claim as new, and desire to secure by Letters Patent, is

1. A lightning-arrester comprising a pair of discharge-plates, a number of sets of polar- 40 izing-cells in series therewith, and a plurality of discharge-plates with jumping-spaces in shunt with the sets of polarizing-cells.

2. A lightning-arrester comprising a counter-electro-motive-force generator divided into sections, in series with a pair of dischargeplatcs, and additional discharge- Hates in series with one another and shunting each section of the counter-electro motive-force generator.

3. The combination, with a pair of discharge-plates in a lightning-arrester, of a plurality of additional discharge-plates in series with one another and with the first-named discharge-plates and separated by jumpingspaces, and connter-electro-motive-force generators shunting some of said spaces.

t. The combination, with the dischargeplatcs of a lightning-arrester, of a counterelectro-motive-force generator in series therewith, consisting of an electrolytic polarizing device.

5. The combination, in a lightning-arrester, with discharge-plates separated by an insulating interval, of a generator of counter electro-motive teree arranged in the dischargepath to oppose the maintenance of an are between the discharge-plates and consisting of a series of metal plates separated by a liquid or moist material, as described.

6. In a lightning-arrester, the combination of the discharge-plates with a set of polarizing-cells in series therewith, comprising metal plates separated by a moist material and sufficient in number to create a counter electromotive force upon the passage of a discharge to earth great enough to prevent arcing at the disruptive space.

In witness whereof I have hereunto set my hand, this 30th day of October, at Lynn, in

the county of Essex and State of Massuchusetts.

E'LlllU THOMSON.

Witnesses:

JOHN W. GIBBONEY, ZENJAMiN B. HULL. 

